Volume 248, 2024

K–O2 electrochemistry at the Au/DMSO interface probed by in situ spectroscopy and theoretical calculations

Abstract

The reaction mechanism underpinning the operation of K–O2 batteries, particularly the O2 reactions at the positive electrode, is still not completely understood. In this work, by combining in situ Raman spectroelectrochemistry and density functional theory calculations, we report on a fundamental study of K–O2 electrochemistry at a model interface of Au electrode/DMSO electrolyte. The key products and intermediates (O2, KO2 and K2O2) are identified and their dependency on the electrode potential is revealed. At high potentials, the first reduction intermediate of O2* radical anions (* denotes the adsorbed state) can desorb from the Au electrode surface and combine with K+ cations in the electrolyte producing KO2via a solution-mediated pathway. At low potentials, O2 can be directly reduced to Image ID:d3fd00071k-t1.gif on the Au electrode surface, which can be further reduced to Image ID:d3fd00071k-t2.gif at extremely low potentials. The fact that K2O2 has only been detected in the very high overpotential regime indicates a lack of KO2 disproportionation reaction both on the Au electrode surface and in the electrolyte solution. This work addresses the fundamental mechanism and origin of the high reversibility of the aprotic K–O2 batteries.

Graphical abstract: K–O2 electrochemistry at the Au/DMSO interface probed by in situ spectroscopy and theoretical calculations

Associated articles

Article information

Article type
Paper
Submitted
22 mars 2023
Accepted
05 mai 2023
First published
09 mai 2023

Faraday Discuss., 2024,248, 89-101

K–O2 electrochemistry at the Au/DMSO interface probed by in situ spectroscopy and theoretical calculations

J. Liu, L. Guo, Y. Xu, J. Huang and Z. Peng, Faraday Discuss., 2024, 248, 89 DOI: 10.1039/D3FD00071K

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